I. Field of the Invention
This invention relates to apparatus for cleaning grain of undesirable foreign material and more particularly to an auger which cleans grain while transporting grain through the auger.
II. Description of the Prior Art
When grain is harvested, it contains a variety of undesirable solid foreign material. Examples of such undesirable material include fines, weed seeds and other trash as well as very light foreign material such as hulls, chaff, insects and bees wings. It is desirable to clean grain of such foreign material in order to improve the quality of the grain product as well as result in less spoilage during storage of the grain and more efficient drying of the grain. The prior art is complete with many separate grain cleaning apparatus which are separate from augers used in grain harvesting operations to transport grain. An example of prior art which teaches a grain cleaning mechanism which acts simultaneous with grain transportation is U.S. Pat. No. 331,967 to Hawley dated Dec. 8, 1885. Hawley teaches a grain elevator which has a trough beneath the elevator. An opening is formed in the trough and covered with a wire screen through which fine seeds and other impurities may pass. U.S. Pat. No. 988,095 to Haugo dated Mar. 28, 1911, teaches a grain auger used in a grain separator. An arcuate screen or sieve member forms a trough for the auger to carry the grain being delivered by the auger. The sieve member functions to separate out small weeds from the grain being carried by the auger. The auger and sieve member are sized such that the auger fits closely against the upper surface of the sieve member so as to physically scrape grain from the sieve in order that the sieve will not become clogged. In both Hawley and Haugo the sieves and troughs are fixed.
Sieves such as taught by Hawley and Haugo permit passing of solid material and may be effective in partial separation of grain from heavier foreign material from the grain. However, grain includes very light foreign material such as insects and bees wings and chaff which, due to their extreme lightness, cannot be properly screened. When vibrated, such light material migrates to the top of the grain and does not fall through a screen. One way to separate light particles is to establish an air current which carries the light particles away from the grain. Examples of grain cleansing apparatus which generate air currents by means of blowers include U.S. Pat. No. 3,348,676 to Karlsson and U.S. Pat. No. 2,718,967 to Potter.
Notwithstanding the current status of the prior art, there is a continuous desire to improve grain cleansing apparatus to improve the quality of the grain cleansing. Also, there is a continuing search for apparatus which minimize the amount of processing necessary to transport and cleanse grain.